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Network Control Function Virtualization for Transport SDN
Young Lee (Huawei), Greg Bernstein (Grotto),
Ning So (Tata), Luyuan Fang (Cisco),
Daniele Ceccarelli (Ericsson), Diego Lopez (Telefonica),
Oscar Gonzalez de Dios (Telefonica)
SDN RG IETF 88 Vancouver
• SDN concept has been applied for transport networks. – Separation of control plane functions from data planes by
GMPLS/ASON control plane technology • Link Discovery (LMP) • Dissemination of Link/Resource Information (OSPF-TE) • Connection/Provisioning (RSVP-TE)
– Global view of a network • TEDB, LSDB give the global domain view of a network
– Logically centralized control • PCE for path computation; Stateful PCE for initiation of path
provisioning (in cooperation with GMPLS signaling)
• There is little value of reinventing these network control protocols.
Transport Network Control
2 IETF 88, Vancouver
IETF Control Plane Architecture
CC: Connection Control NE: Network Element
CCI: Connection Control Interface NMI: Network Management Interface
CC
CC
CC CC
CC
NE
NE NE
NE
NE
Management
Plane
NMI
NMI
CCI
GMPLS
PCE
GMPLS Control Plane
• Neighbor Discovery & Link/Resource discovery (LMP) • Routing (OSPF-TE/ISIS-TE) • Signaling (RSVP-TE)
Transport Plane
3 IETF 88, Vancouver
Is there a need to virtualize network control function?
- Why?
- How?
4 IETF 88, Vancouver
Client Control
CC
CC
CC CC
CC
NE
NE NE
NE
NE
CCI
GMPLS
PCE
Client End
Point
Client End
Point
Client End
Point Client End
Point
Client Controller
Applications
• Supports various applications via various NB APIs (e.g., OpenStack, etc.)
• Various types of client to network – Data Center Operators – Virtual Network Providers – Contents Providers – Carriers of carrier
• Primary source for application service/connectivity requirements and location information (client end points).
Network Control
But current GMPLS/PCE architecture does not support programmable interfaces for network virtualization 5 IETF 88, Vancouver
Virtual Network Control Layer
CC
CC
CC CC
CC
NE
NE NE
NE
NE
CCI
GMPLS
Client End
Point
Client End
Point
Client End
Point Client End
Point
Client Controller
Applications
Virtual Network Control Layer
Network Control
• Virtual Network Control separated from Physical network control – Open interfaces creation
– Third party developer can develop VNC layer
• Virtual Network Control Layer provides virtual network control functions: – Virtual Service Creation
– Virtual Path Computation
– Virtual Topology Database Creation
– Virtual Network Discovery
– Topology Abstraction for Virtual Service
– Virtual connection setup
6 IETF 88, Vancouver
Use-case A: application-specific topology abstraction and virtual control
Client B Controller
VNC
Client C Controller
Client A Controller
4 1
2
5
6
5 1
2
5
6
1 1
2
3
4
5
6
3
4
3
4
7
8
A.1
A.2
A.3
B.1 B.2
B.3
C.2 C.3
2 1
2
3
4 5
6
3 1
2
3
4
5
6
PNC
Creates abstraction topology per application/client need
4 1 6
5 2
1 1 3
6
4
3 8
A.1
A.2
A.3
2 1 4 5
3 2 3
6
5 1
1 1 3
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3 1 3
5
B.1 B.2
B.3
1
8
3
C.1
C.2
C.3
network topology
Use-case B1: Dynamic DCI in multi-domain network (Topology Request)
DC Controller
VNC
PNC 1
PNC 2
PNC 3
DC1
DC2
DC3 DC4
DC5
DC6
Network 1 Network 3
Network 2
1. Topology Request: Endpoints list
2. Topology Request: Endpoints list, peering point
3. Abstracted Topology
4. E2E Abstracted Topology
8 IETF 88, Vancouver
Use-case B2: Dynamic DCI in multi-domain network (Connection Request)
DC Controller
VNC
PNC 1
PNC 2
PNC 3
DC1
DC2
DC3 DC4
DC5
DC6
Network 1 Network 3
Network 2
1. Connect Request:1-6
3. Connect
2. V_Path Compute
9 IETF 88, Vancouver
Client Control Layer
Physical Network Control Layer
Virtual Network Control Layer SDN
Network Control
SDN Client Control
Application Layer
Client-VNC Interface (CVI)
VNC-PNC interface (VPI)
South Bound Interface (e.g., GMPLS CCI)
Physical Network Control Layer
Physical Network Control Layer
Client Control Layer Client Control Layer
Interfaces
10 IETF 88, Vancouver
Control Workflows
Physical Network Control
Virtual Network Control
Client Control
1. VNS Instantiation (instance id, traffic matrix)
2. Path computation request
3. Path computation reply with updated topology
4. Abstracted topology
5. VNS Set-up Command
6. Network Provisioning Request
VNS Control
VNS Proxy
vPCE Agent
PCE Network Provisioning
vConnetion Agent
7. Network Provisioning Confirm
8. VNS Set-up Confirm
11 IETF 88, Vancouver
• Which network control functions can be virtualized? – V-path computation
– Abstraction topology database creation
– V-connection
– others??
• What is the right level of client control?
• How to represent abstracted topology? – Granularity level of topology abstraction
– Information hiding without losing bottleneck link resource information
– Modeling tool: JSON based, …
• Who owns virtual network control?
• Related work on topology abstraction – ALTO topology Service [I-D.yang-alto-topology]& [I-D.lee-alto-app-net-info-exchange]
– OGF NML: General framework for multi-layer network modeling in XML/RDF based on ITU-T G.800
• If you are interested in this work, more discussion will be held, 8:30-9:30pm, November 5 (today) @Plaza B
IETF 88, Vancouver
Work Items
12
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